// Copyright 2014 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef MEDIA_CAST_RECEIVER_AUDIO_DECODER_H_
#define MEDIA_CAST_RECEIVER_AUDIO_DECODER_H_

#include "base/callback.h"
#include "base/macros.h"
#include "base/memory/ref_counted.h"
#include "media/base/audio_bus.h"
#include "media/cast/cast_environment.h"
#include "media/cast/constants.h"
#include "media/cast/net/cast_transport_config.h"

namespace media {
namespace cast {

    class AudioDecoder {
    public:
        // Callback passed to DecodeFrame, to deliver decoded audio data from the
        // decoder.  The number of samples in |audio_bus| may vary, and |audio_bus|
        // can be NULL when errors occur.  |is_continuous| is normally true, but will
        // be false if the decoder has detected a frame skip since the last decode
        // operation; and the client should take steps to smooth audio discontinuities
        // in this case.
        typedef base::Callback<void(std::unique_ptr<AudioBus> audio_bus,
            bool is_continuous)>
            DecodeFrameCallback;

        AudioDecoder(const scoped_refptr<CastEnvironment>& cast_environment,
            int channels,
            int sampling_rate,
            Codec codec);
        virtual ~AudioDecoder();

        // Returns STATUS_INITIALIZED if the decoder was successfully constructed.  If
        // this method returns any other value, calls to DecodeFrame() will not
        // succeed.
        OperationalStatus InitializationResult() const;

        // Decode the payload in |encoded_frame| asynchronously.  |callback| will be
        // invoked on the CastEnvironment::MAIN thread with the result.
        //
        // In the normal case, |encoded_frame->frame_id| will be
        // monotonically-increasing by 1 for each successive call to this method.
        // When it is not, the decoder will assume one or more frames have been
        // dropped (e.g., due to packet loss), and will perform recovery actions.
        void DecodeFrame(std::unique_ptr<EncodedFrame> encoded_frame,
            const DecodeFrameCallback& callback);

    private:
        class ImplBase;
        class OpusImpl;
        class Pcm16Impl;

        const scoped_refptr<CastEnvironment> cast_environment_;
        scoped_refptr<ImplBase> impl_;

        DISALLOW_COPY_AND_ASSIGN(AudioDecoder);
    };

} // namespace cast
} // namespace media

#endif // MEDIA_CAST_RECEIVER_AUDIO_DECODER_H_
